Abstract: The invention aims to prevent the disadvantages of printed circuit board transformers with respect to their quality and safety, in particular in a performance range of greater than 150 VA with output voltages of less than 12 V. This is achieved by a planar transformer comprising a ferrite core (1a, 1b, 21a, 21b), at least one primary coil and at least one secondary coil, which can be connected on a printed circuit board and a coil body (3, 23), which encompasses part of the ferrite core (1a, 1b, 21a, 21b) and carries at least one secondary coil. According to the invention, each of the secondary coils (3, 23) carried by the coil body is configured from at least one winding metal sheet (2, 22), which is open on one side and can be plugged into the coil body (3, 23) and connected to the printed circuit board.

Abstract: A multilayer structure in which all the magnetic elements have the windings edged in the inner layers and the magnetic core which surrounds the winding has the legs penetrating through the multilayer structure. The interconnection between the magnetic elements and the rest of electronic components is done through the layers of the multilayer board, horizontally and vertically through via. For higher power components special cuts are performed in the multilayer board to accommodate the body of the components which may be connected to an external heatsink. The winding arrangement in the transformer is done in a such way to minimize and even eliminate the common mode noise injected through the capacitance between primary and secondary winding. The input filter is constructed to exhibit a differential and a common mode impedance.

Abstract: A storage magnetic element, which minimizes the power loss in the planar winding due to the fringe magnetic field associated with a discrete air gap, is presented. The invention describes a construction technique wherein the magnetic core is formed by an E section made of high permeability magnetic material and an I section made by a material capable to store energy due to its distributed gap structure. The I section of the magnetic core in one of the embodiments is covered by an electrically conductive shied to force the magnetic flux into the I section and to minimize the component of the fringe magnetic field perpendicular on the planar winding. In another embodiment of this invention the electrically conductive shield is replaced by a high magnetic permeability material to accomplished the same goal of reducing the magnetic field component perpendicular on the planar winding.

Abstract: The present invention is a circuit and method for reducing switching and reverse recovery losses in the output rectifiers while creating zero voltage switching conditions for the primary switchers. There are described two output configurations, one employing a soft commutation inductor element a bridge rectifier and a output filter capacitor, the second using a soft commutation inductor element a rectification-filtering bridge composed by two capacitors and two capacitors. Both secondary circuits can be driven by three primary circuits. A first circuit is a full bridge with phase shift control, and a second circuit is a half bridge topology with an additional bydirectional switch which achieves two goals, on to get soft switching commutation across all the primary switches, the second to create the right waveforms in the secondary suitable with the claims in this invention. The third topology is a phase shifted two transistors forward.

Abstract: A power supply circuit comprising an active power factor correction circuit. The active power factor correction circuit comprises a controller for controlling both the power factor correction and the inrush current control circuit. The inrush control circuit comprises at least one insulated gate bipolar transistor (IGBT) connectable to the controller.

Abstract: An apparatus for converting a three-phase voltage system to a DC voltage is supported by an output capacitor and a star circuit. On the input side of filter capacitors is a controllable three-phase bridge and at a positive output of the bridge circuit, a current-stabilizing inductance is included, which, in conjunction with a step-up controller diode and a step-up controller transistor, forms a DC voltage/DC voltage step-up controller which is integrated in the converter structure. The phase arms of the three-phase bridge have an identical structure and their conductance state can be controlled by control switches. In order to produce an output voltage from the system which is below the mean value of the maximum output voltage of the bridge circuit, the step-up controller transistor remains in the switched-off state, and a voltage value which is above the maximum output voltage is formed.